Where to Find the File Cabinet Keys in Blue Prince (& How to Use Them)

While exploring the Billiard Room or the Blue Door, you’ve probably come across File Cabinet Keys in Blue Prince. Now, you might be wondering what they unlock and where to use them. These keys are scattered throughout the manor and its surrounding areas, but the game doesn’t provide many hints about their purpose. While they’re not essential for completing the game, these keys unlock hidden drawers that contain valuable items, cryptic documents, and clues to other puzzles.

In this guide, we’ll show you where to find the File Cabinet Keys in Blue Prince and explain how to use the File Cabinet Keys in Blue Prince to unlock hidden rewards and solve puzzles.

Finding File Cabinet Keys in Blue Prince

Clues for File Cabinet Keys #1 and #2

The first two File Cabinet Keys can be found by following clues in the Aquarium. However, you’ll only see these clues after fully draining the water using the Pump Room. To do this, you may also need to activate the Boiler Room to make use of the reserve tank.

Once the water is drained, the aquariums will display dioramas of rooms in the mansion. Two of these dioramas have floors marked with an “X” symbol, hinting at where you need to dig to find the keys.

Where to Find File Cabinet Keys #1 and #2

The two rooms you need to visit are the Patio and the Laundry Room. Make sure to bring a Shovel with you, as you’ll need it to dig up the keys. Stand in the correct spot to see the dig icon appear.

• Patio: The dig spot is in front of the left-hand side of the barbecue grill.
• Laundry Room: Look for three washing machines on the right side of the room. The dig spot is in front of the middle washing machine.

Which Drawers Do File Cabinet Keys #1 and #2 Unlock?

Once you’ve found the keys, it’s time to figure out where to use them. The clue comes from the Safehouse, which becomes accessible after fully draining the Reservoir. Inside the Safehouse, you’ll find a document pointing to a set of terminals resembling those in the Security Room. By examining the CCTV footage, you’ll notice it highlights a specific file cabinet in the Archives.

Take the keys to the Archives and unlock the corresponding drawers:

• The Patio key opens the bottommost drawer, which contains an Upgrade Disk and a birth certificate.
• The Laundry Room key opens the drawer just above it. This drawer contains cryptic documents, including clues related to the Sanctum Sigil Puzzle.

Where to Look for File Cabinet Key #3

The third File Cabinet Key is located outside the manor, in a dark tunnel filled with crates. To access it, you’ll need to follow these steps:

• Early on, bring an item that can light torches to pick up the Tunnel Floorplan.
• After completing the Laboratory Puzzle, collect all three Microchips and place them in the Sundial. This will allow you to download a data packet containing new laboratory experiments.
• Use the new experiments to remove the crates blocking the tunnel.
• After clearing about a dozen crates, you’ll find a wooden box left behind. Open it to retrieve the third File Cabinet Key.

File Cabinet Key #3: Which Drawer Does It Unlock?

This key unlocks a drawer in the Underground, specifically in the foreman’s hidden office near the Rotating Gear Puzzle. The office connects the Rotating Gear to the tunnel with the mine cart. Inside the drawer, you’ll find another document containing a riddle.

And that’s all you need to know about the File Cabinet Keys in Blue Prince. If you’re feeling stuck or need help with other puzzles, be sure to check out our other Blue Prince guides on RetroNoob.